JP3216484B2 - Automotive steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system, and more particularly to a vehicle steering system using a universal joint.

[0002]

2. Description of the Related Art Generally, a steering device for a vehicle is known as a device for giving a steering angle to wheels by rotating a steering wheel. This steering apparatus for a vehicle generally includes a steering wheel operated by a driver, a steering shaft connected to the steering wheel and rotating, a gear box for converting the rotational force of the steering shaft into a linear movement of a rack bar, and a rack bar. It is composed of a knuckle arm or the like that steers wheels as it moves.

[0003] The steering shaft has an input shaft having an upper end connected to the steering, an output shaft having a lower end connected to the gear box, and an intermediate shaft disposed between the input shaft and the output shaft. , A first hook joint connecting the lower end of the input shaft and the intermediate shaft, a second hook joint connecting the upper end of the output shaft and the intermediate shaft, and the like.

Further, the first hook joint has a configuration in which an input shaft side yoke provided on the input shaft and an intermediate shaft side yoke provided on the intermediate shaft are joined by a cross pin.
The hook joint has a configuration in which an output shaft side yoke provided on the output shaft and an intermediate shaft side yoke provided on the intermediate shaft are joined by a cross pin.

An example of this type of vehicle steering system is disclosed in Japanese Patent Laid-Open Publication No. Hei 6-321118. The vehicle steering apparatus disclosed in the publication has an arrangement in which, when the steering angle is zero, the input shaft-side yoke is arranged to be perpendicular to a plane including the input shaft and the intermediate shaft, and the output shaft-side yoke is arranged. Are arranged perpendicular to a plane including the intermediate axis and the output axis, and the intersection angle between the input axis and the intermediate axis is different from the intersection angle between the intermediate axis and the output axis. With this configuration, the steering torque can be easily set to the peak or the valley of the torque fluctuation.

[0006]

By the way, flutter is known as a phenomenon that the steering vibrates in the circumferential direction during traveling. This flutter is caused by resonance of the suspension and steering system due to unbalance and non-uniformity of the wheels.

Here, the reason why flutter occurs due to the vibration of the tire will be described with reference to FIGS. In the drawings, reference numeral 1 denotes a steering, which is connected to a gear box 6 via an input shaft 3, an intermediate shaft 4, and an output shaft 5 constituting a steering shaft 2. Also,
The input shaft 3 and the intermediate shaft 4 are connected by a first hook joint 7, and the intermediate shaft 4 and the output shaft 5 are connected by a second hook joint 8. Further, the gear box 6 has a rack bar 9 inside.
Is inserted through the sub-frame 10 (rack housing 11).
The rack 12 formed on the rack bar 9 and the pinion 13 provided at the lower end of the output shaft 5 mesh with each other in the gear box 6.

[0008] The following two types of reasons why flutter occurs due to tire vibration are considered. One of them is pinion 13
The other is flutter generated by the translational vibration of the gear box 6 (shown in FIG. 26).

First, the flutter generated by the rotation of the pinion 13 will be described. If the wheels have an imbalance or non-uniformity as described above, forced vibrations are generated on the wheels during running of the vehicle. This forced vibration is transmitted to the rack bar 9 via a knuckle arm (not shown), so that the rack bar 9 vibrates in the axial direction (lateral direction).

Then, relative vibration in the axial direction of the rack bar 9 (indicated by an arrow in FIG. 25) is generated inside the rack housing 11, and the pinion 1 is caused by the relative vibration.
Rotational vibration occurs in 3. The rotational vibration of the pinion 13 is
The vibration is transmitted to the steering wheel 1 via the steering shaft 2, and as a result, circumferential vibration (flutter) occurs in the steering wheel 1.

Next, the flutter generated by the translational vibration of the gear box 6 will be described. When the forced vibration occurs in the wheels as described above, the sub-frame 10 vibrates in the axial direction (indicated by an arrow A in FIG. 26) due to the forced vibration.
Accordingly, the gear box 6 provided on the sub-frame 10 also translates and vibrates in the axial direction with respect to the vehicle body (not shown). The forced vibration also occurs in the vertical direction and the vehicle longitudinal direction in addition to the above-described axial direction. Therefore, the translational vibration of the gear box 6 also occurs in the vertical direction and the vehicle longitudinal direction.

On the other hand, since the input shaft 3 constituting the steering shaft 2 is supported by the vehicle body, when the gear box 6 translates and vibrates as described above, the input shaft 3 is located between the gear box 6 and the input shaft 3. Relative vibration occurs. This relative vibration is converted into rotational vibration at each of the hook joints 7 and 8, and as a result, circumferential vibration (flutter) occurs in the steering 1.

However, the vehicle steering system disclosed in the above-mentioned publication does not take any measures for suppressing flutter generated for the reason described with reference to FIGS. 25 and 26. Although the steering torque can be easily set to the peak or valley of the torque fluctuation, there is a problem that flutter cannot be effectively prevented.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a rotary vibration generated on an output shaft by forced vibration of a wheel is bent and deformed by a low-rigid member provided on an input shaft, an intermediate shaft or an output shaft. And the input shaft, intermediate shaft, and output shaft are arranged in the same plane, and the yokes on the input shaft side and the output shaft side are arranged perpendicular to the plane, thereby forcing the vibration of the wheels. It is an object of the present invention to provide a steering apparatus for an automobile in which flutter is prevented from occurring by configuring so that translational vibration of a gear box generated by the above is not converted into rotational vibration at each joint.

[0015]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by taking the following means. According to the first aspect of the present invention, at least two shafts including at least an input shaft connected to the steering wheel and an output shaft connected to the gear box are provided, and a pair of connected shafts is connected by a universal joint. In the vehicle steering apparatus having the above configuration, when the vehicle is traveling straight, one of the yokes constituting the universal joint is disposed so as to be substantially perpendicular to a plane including the pair of shafts, and is arranged so as to be substantially perpendicular. With the yoke placed on the shaft side, the bending direction of the shaft
It is characterized in that a low rigidity member for lowering the rigidity is provided.

According to the second aspect of the present invention, the input shaft connected to the steering is connected to the intermediate shaft via the first universal joint, and the intermediate shaft is connected to the gear box via the second universal joint. In a vehicle steering system having a configuration connected to an output shaft connected to the vehicle, the input shaft, the intermediate shaft, and the output shaft connected to the first universal joint hand and the second universal joint when the vehicle travels straight ahead are respectively provided. The yoke on the input shaft side and the yoke on the output shaft side are arranged to be substantially perpendicular to the plane while being arranged in the same plane.

According to a third aspect of the present invention, in the vehicle steering system according to the second aspect, at least one of the input shaft and the output shaft has a lower rigidity in a bending direction of the shaft.
A low-rigidity member is provided.

The means described above operates as follows. According to the first aspect of the invention, when the vehicle travels straight, one of the yokes constituting the universal joint is disposed so as to be substantially perpendicular to a plane including the pair of shafts, so that torque transmission is performed in the universal joint. When this occurs, a bending moment is generated on an axis having a yoke substantially perpendicular to the plane.

Further, by providing a low-rigid member on the shaft having a yoke arranged to be substantially vertical, that is, a shaft where a bending moment is generated, the low-rigid member is bent by applying a bending moment. It deforms and the equivalent torsion spring constant decreases. Therefore, when rotational vibration occurs in the pinion due to the forced vibration of the wheels, the rotational vibration is absorbed by the low-rigidity member having a reduced equivalent torsion spring constant, so that the rotational vibration can be prevented from being transmitted to the steering. The occurrence of flutter can be prevented.

According to the second aspect of the present invention, when the vehicle is traveling straight, the input shaft, the intermediate shaft, and the output shaft connected by the first and second universal joints are arranged in the same plane, respectively. By arranging the yokes on the input shaft side and the output shaft side perpendicular to the plane, the pins pivoted on the yokes on the input shaft side and the output shaft side are in a state of being arranged in parallel.

The yokes arranged on the input shaft side and the output side of the intermediate shaft are arranged perpendicular to the yokes on the input shaft side and the output shaft side. The pin thus set is placed in parallel with the plane. That is, each pin disposed between the input shaft side yoke and the intermediate shaft side yoke constituting the first universal joint,
The pins arranged between the yoke on the output shaft side and the yoke on the intermediate shaft side, which constitute the universal joint, are arranged in a three-dimensional parallel relationship. In this configuration, even if the translational vibration occurs in the gear box as described above, the translational vibration is not converted into the rotational vibration in each joint, so that the occurrence of flutter can be prevented.

According to a third aspect of the present invention, in the configuration of the vehicle steering apparatus according to the second aspect,
By arranging the low-rigidity member on at least one of the input shaft and the output shaft where a bending moment is generated in the same manner as in the first aspect of the present invention, both the above-mentioned functions of the first and second aspects can be achieved. An automobile steering system can be realized.

That is, when rotational vibration occurs in the pinion due to forced vibration of the wheel, the rotational vibration is disposed on a shaft where a bending moment is generated, thereby reducing the equivalent torsion spring constant of a low-rigid member. Because of the absorption, the occurrence of flutter can be prevented. In addition, when translational vibration occurs in the gear box due to forced vibration of the wheels, each universal joint does not convert the translational vibration into rotational vibration, so that the translational vibration is cut off, thereby preventing the occurrence of flutter.

[0024]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a vehicle steering system 20 according to a first embodiment of the present invention. In the figure, reference numeral 21 denotes a steering, and a steering shaft 2
2 is connected to the gear box 26. The steering shaft 22 according to the present embodiment includes three shafts, an input shaft 23, an intermediate shaft 24, and an output shaft 25. The steering 21 is provided at the upper end of the input shaft 23, and a pinion 35 described below is provided at the lower end of the output shaft 25.

The input shaft 23 to which the steering wheel 21 is attached is supported by the vehicle. Therefore, even if a vibration occurs in the gear box 26, the input shaft 23 is not displaced by the vibration. ing. Further, the input shaft 23 and the intermediate shaft 24 are connected by a first hook joint 30, and the intermediate shaft 24 and the output shaft 25 are connected by a second hook joint 31.

The first hook joint 30 includes an input shaft side yoke 27 which rotates integrally with the input shaft 23, and an intermediate shaft side yoke 28 which is formed at the upper end of the intermediate shaft 24 and rotates integrally with the intermediate shaft 24. And a cross pin 29 and the like rotatably connected to the yokes 27 and 28. Also,
The second hook joint 31 is formed at a lower end portion of the intermediate shaft 24 and is provided on an intermediate shaft side yoke 32 which rotates integrally with the intermediate shaft 24.
And an output shaft side yoke 33 that rotates integrally with the output shaft 25.
And a cross pin 34 and the like rotatably connected to the yokes 32, 33.

On the other hand, the gear box 26 is disposed on a sub-frame 37 (having a rack housing 39) into which a rack bar 36 is inserted.
The pinion 35 formed at the lower end of the output shaft 25 meshes with the rack 38 formed in the gear box 26. Both ends of the rack bar 36 are connected to wheels via knuckle arms (not shown). The output shaft 25 is provided with a rubber coupling 40, which is a low-rigidity member, which is one of the main parts of the present embodiment. For convenience of explanation, the rubber coupling 40 will be described later. .

According to the steering apparatus 20 for a vehicle configured as described above, when the driver operates the steering wheel 21, the operating force is applied to the input shaft 23, the first hook joint 30, and the intermediate shaft 2.
4, transmitted to the gear box 26 via the second hook joint 31 and the output shaft 25. In the gear box 26, the pinion 35 provided at the lower end of the output shaft 25 and the rack 38 formed on the rack bar 36 mesh with each other. (In the directions indicated by arrows A1 and A2 in the drawing), and the wheels are steered via knuckle arms provided at both ends of the rack bar 36.

Here, the vicinity of the disposition position of the second hook joint 31 is shown in FIGS. 2 and 3 in an enlarged manner, and the arrangement of the yokes 32 and 33 and the rubber coupling 40 in this embodiment are shown.
The function of will be described. In the present embodiment, assuming a plane S1 including a pair of the intermediate shaft 24 and the output shaft 25, when the steering angle of the steering 21 at the time of straight traveling of the vehicle is zero, the second hook is attached to the plane S1. One of the yokes constituting the joint 31 is arranged to be substantially vertical. Specifically, in the vehicle steering system 20 according to the present embodiment, the output shaft side yoke 33 disposed on the output shaft 25 is configured to be substantially perpendicular to the plane S1. In addition, by making the output shaft side yoke 33 substantially perpendicular to the plane S1, the intermediate shaft 24
Are arranged substantially parallel to the plane S1.

Next, each of the yokes 32,
In the second hook joint 31 having the
Consider the balance of forces when the two are performed. Now
Rubber coupling 40 is not provided on output shaft 25
Assuming the configuration, the intersection angle between the intermediate shaft 24 and the output shaft 25
Is φ, and torque T is applied to the output shaft 25 during torque transmission. ₀
Is torque T on the intermediate shaft 24.₁Is generated.

At this time, since the intermediate shaft side yoke 32 provided on the intermediate shaft 24 is parallel to the plane S1, no bending component is generated, and only the pure torque T1 is generated. This intermediate shaft 2
The torque T1 generated at 4 is represented by T1 = F1 * L, where L is the length of the intermediate shaft side yoke 32 and F1 is the rotational force. On the other hand, the resistance to balance the rotational force F1 of the intermediate shaft 24
As the force , the torque T0 of the output shaft 25 causes the output shaft side yoke 33 to generate a rotational force F1 in the illustrated direction based on the intersection angle φ.

In this case, the rotational force F1 of the output shaft 25 includes a component force F0 for rotating the output shaft 25 based on the torque T0 of the output shaft 25, and a component force FM acting as a bending moment of the output shaft 25. Occurs. The component force F0 is based on the torque T0 of the output shaft 25. Therefore, the torque T0 of the output shaft 25 is represented by T0 = F0 × L where L is the length of the output shaft side yoke 33. As described above, a component force FM is generated on the output shaft 25, and the component force FM generates a bending moment on the output shaft 25. The bending moment M generated on the output shaft 25 is M = FM × L. Is shown.

As described above, when the two shafts 24 and 25 are connected by the hook joint 31, a bending moment M is generated on one of the shafts. The axis (the output axis 25 in the example of FIG. 2) having a yoke perpendicular to the plane S1 including the axis S25.

Here, assuming a configuration in which the rubber coupling 40 is disposed again, the bending moment M generated as described above is reduced by the rubber coupling 40 having a low bending rigidity.
To cause bending deformation in the rubber coupling 40, it is possible to reduce the equivalent torsional rigidity of the rubber coupling 40. Further, when the equivalent torsional rigidity of the rubber coupling 40 is reduced, the rotational vibration of the pinion 35 is absorbed by the rubber coupling 40, so that flutter can be prevented.

More specifically, as described above, in the flutter generated by the rotation of the pinion 35, the forced vibration generated in the wheels is transmitted to the rack bar 36, and the rack housing 39 and the rack bar 36 are relatively vibrated. As a result, rotational vibration occurs in the pinion 35, and the rotational vibration of the pinion 35 is transmitted to the steering 21 via the steering shaft 22. Accordingly, a member having low torsional rigidity (low rigidity member) is provided at a position halfway from the pinion 35 to the steering 21 and the rotational vibration of the pinion 35 is absorbed by the low rigidity member to prevent flutter. be able to.

In the present embodiment, the bending moment generated on the output shaft 25 at the hook joint 31 is
0, thereby reducing the equivalent torsional rigidity of the rubber coupling 40, and preventing the occurrence of flutter by absorbing the rotational vibration of the pinion 35 generated when the wheel is forcibly vibrated by the rubber coupling 40. It is configured to do so.

FIG. 3 shows the behavior of the rubber coupling 40 with the bending moment applied and the respective shafts 24 and 25 at this time. FIG. 3 (A) shows an automobile steering system 2.
0 is a plan view, and (B) is a side view of the vehicle steering device 20. As shown in FIG. 3A, when a bending moment M is applied to the rubber coupling 40, bending deformation occurs in the rubber coupling 40. Now, assuming that the bending angle of the rubber coupling 40 is Δθ _M and the bending rigidity of the rubber coupling 40 is Kθ _M , the bending angle is Δ
θ _M is obtained as Δθ _M = _M / Kθ _M. Further, as shown in FIG. 3 (B), by applying a bending moment M to the rubber coupling 40, a shaft rotation amount ΔN is generated on the intermediate shaft 24, and the shaft rotation amount ΔN is equal to the intersection angle φ. And ΔN = Δθ _M · sin φ.

As described above, the bending moment generated at the hook joint 31 causes the rubber coupling 40 to be bent and deformed, whereby the equivalent torsional rigidity of the rubber coupling 40 can be reduced. Here, how the equivalent torsional rigidity of the steering system changes depending on the arrangement position of the rubber coupling 40 and the presence or absence of bending deformation of the rubber coupling 40 will be considered. In the following description, a change in the equivalent torsional rigidity is determined as a change in the equivalent torsional spring constant of the steering system.

FIGS. 4 to 7 show an automobile steering system in which the arrangement position of the rubber coupling 40 is variously changed. In each figure, the same reference numerals are given to the components corresponding to the components shown in FIG. The vehicle steering device 20A shown in FIG. 4 and the vehicle steering device 20B shown in FIG. 5 have an intermediate shaft-side yoke 28 of the first hook joint 30 when the steering angle when the vehicle is traveling straight is zero.
Are arranged perpendicular to the plane including the input shaft 23 and the intermediate shaft 24, and the intermediate shaft side yoke 32 of the second hook joint 31 is perpendicular to the plane including the intermediate shaft 24 and the output shaft 25. It is configured so as to be arranged.

The vehicle steering system 2 shown in FIG.
7C, the steering yoke 27 of the first hook joint 30 is perpendicular to the plane including the input shaft 23 and the intermediate shaft 24 when the steering angle is zero. And the second
The output shaft side yoke 33 of the hook joint 31 is arranged to be perpendicular to a plane including the intermediate shaft 24 and the output shaft 25.

Therefore, in the vehicle steering devices 20A and 20B shown in FIGS. 4 and 5, a bending moment is generated on the intermediate shaft 24 for the reason described with reference to FIG. For the same reason, in the vehicle steering devices 20C and 20D shown in FIGS.
Generates a bending moment. Therefore, a configuration in which the rubber coupling 40 is disposed on a shaft where a bending moment is generated, and a configuration where the rubber coupling 40 is disposed on a shaft where a bending moment is not generated can be considered.

Therefore, the steering devices 20A and 20C for automobiles shown in FIGS. 4 and 6 have a structure in which a rubber coupling 40 is disposed on a shaft where no bending moment is generated, and shown in FIGS. 5 and 7. Vehicle steering system 20
B and 20D have a configuration in which a rubber coupling 40 is disposed on a shaft where a bending moment is generated. Although the configuration shown in FIG. 4 shows a configuration in which the rubber coupling 40 is provided on the output shaft 25, the equivalent torsion spring constant is the same even if the rubber coupling 40 is provided on the input shaft 23. Becomes Similarly, even if the rubber coupling 40 is provided on the input shaft 23 in FIG.
It is the same value as the configuration arranged in

As described above, the configuration of the vehicle steering system is classified into four cases shown in FIGS. 4 to 7 according to the configuration of each of the hook joints 30 and 31 and the arrangement position of the rubber coupling 40. Therefore, a formula for calculating an equivalent torsion spring constant is calculated for each of the vehicle steering devices 20A to 20D of each configuration, and the formula is calculated based on the formula.
Characteristics of ～20D (e.g., intersection angle φ, etc.) to determine the equivalent torsional spring rate of the steering system by substituting specific values of the characteristics of and the rubber coupling 40 (for example, bending stiffness K [theta _M, etc.). The following table shows the results of exponentially displaying the equivalent torsion spring constants when the single spring constant of the rubber coupling 40 is 100 when each hook joint of the steering system has a predetermined intersection angle φ. Show. The results in the table below are
This is a value when the intersection angle φ is fixed. Therefore, if the intersection angle φ changes, the following table also changes.

[0044]

[Table 1]

From the results shown in Table 1, it can be seen that the vehicle steering device 20D shown in FIG. 7 has the lowest equivalent torsion spring constant (this configuration is the same as that of the vehicle steering device 20 shown in FIG. 2). Is). That is, when the steering angle at the time of straight traveling of the vehicle is zero, the input shaft side yoke 27 of the first hook joint 30 is arranged to be perpendicular to the plane including the input shaft 23 and the intermediate shaft 24, and The output shaft side yoke 33 of the second hook joint 31 is arranged to be perpendicular to a plane including the intermediate shaft 24 and the output shaft 25, and a shaft (an output shaft 25 or an input shaft 23) where a bending moment is generated. By disposing the rubber coupling 40 in the above, the equivalent torsion spring constant can be reduced.

As described above, since the equivalent torsion spring constant can be reduced, the rotational vibration of the pinion 35 generated when the wheel is forcibly vibrated can be reduced.
Therefore, no vibration is generated on the steering side of the rubber coupling 40, and the occurrence of flutter can be prevented.

As described above, the steering apparatus 20D for an automobile shown in FIG. 7 has the lowest equivalent torsion spring constant, and thus can most effectively prevent the occurrence of flutter. The reduction of the equivalent torsion spring constant is also recognized in the vehicle steering device 20B. That is, when the steering angle at the time of straight traveling of the vehicle is zero, the intermediate shaft side yoke 28 of the first hook joint 30 is arranged to be perpendicular to the plane including the input shaft 23 and the intermediate shaft 24, and The second shaft joint yoke 32 of the second hook joint 31 is disposed so as to be perpendicular to a plane including the intermediate shaft 24 and the output shaft 25, and the shaft (the intermediate shaft 2) where a bending moment is generated.
Even in the configuration in which the rubber coupling 40 is provided in 4), the flutter can be prevented from occurring although the characteristics are slightly worse than the vehicle steering device 20D.

On the other hand, from a different point of view, the steering devices 20A and 20C shown in FIGS. 4 and 6 have a large equivalent torsion spring constant, so that the steering wheel at a steering angle near zero (ie, near neutral). The rigidity of the operation can be increased. Therefore, the vehicle steering devices 20A and 20C shown in FIGS. 4 and 6 have a large effect when applied to a vehicle that places importance on the steering feel near neutral.

By the way, in the configuration of the vehicle steering apparatus 20D, as described above, the equivalent torsion spring constant is low, and the flutter can be effectively prevented. The generated steering angle is affected not only in a region near zero (hereinafter, this region is referred to as a flutter region), but also in a region in which the steering wheel 21 is operated to change the vehicle direction (hereinafter, this region is referred to as a steering region). Exert. If the equivalent torsion spring constant is low even in the steering region as described above, the steering operation force is absorbed by the rubber coupling 40, and the responsiveness may be degraded and the steerability may be degraded.

However, this problem can be solved by using the rubber coupling unit 45 shown in FIG. The rubber coupling unit 45 has a configuration in which the rubber coupling 40 is disposed between a flange 46 that forms a part of the second hook joint 31 and a flange 47 that is formed integrally with the output shaft 25. Have been. A small hole 4 having a predetermined diameter is provided at the center of the flange 46.
The centering shaft 49 provided at the tip of the output shaft 25 so as to extend in the axial direction is inserted into the small hole 48. A stopper 50 having excellent wear resistance is provided on the inner wall of the small hole 48.

With the rubber coupling unit 45 having the above configuration, the centering shaft 49 is
8 is displaceable inside. That is, the centering shaft 49 can be displaced in the small hole 48 by the gap formed between the centering shaft 49 and the stopper 50. The size of the gap is configured to correspond to the flutter area described above.

Therefore, in the rubber coupling unit 45 having the above configuration, the centering shaft 49 is
6 before and after contact with the rubber coupling 40.
Can be changed. That is, before the centering shaft 49 comes into contact with the flange 46, the rubber coupling 40 is in a state where it can be bent by the bending moment generated in the output shaft 25, and thus the equivalent torsion spring constant becomes a low value. .

After the centering shaft 49 comes into contact with the flange 46, the flange 46 and the flange 4
The rubber coupling 40 cannot be bent because the relative displacement with respect to 7 is restricted. Therefore, the equivalent torsional spring constant of the rubber coupling 40 becomes the original torsional spring constant of the rubber coupling (when no bending occurs).

FIG. 9 shows the equivalent torsion spring characteristics of the rubber coupling unit 45. As described above, the size of the gap formed between the centering shaft 49 and the stopper 50 is configured to correspond to the flutter area. Therefore, the equivalent torsion spring characteristic of the rubber coupling unit 45 is such that the equivalent torsion spring constant of the rubber coupling 40 is small in the flutter region where flutter may occur, and the steering region in which the wheels are steered. Has a large non-linear characteristic.

With this configuration, in the flutter area, the equivalent torsion spring characteristic of the rubber coupling 40 is small, and the pinion 35 is caused by the forced vibration of the wheel.
Even if rotational vibration occurs, the rotational vibration can be absorbed by the rubber coupling 40, so that the occurrence of flutter can be prevented. In the steering region, the equivalent torsion spring characteristic of the rubber coupling 40 is an original value due to the centering shaft 49 abutting on the flange 46, so that a steering response with good responsiveness can be obtained. Can be.

That is, by providing the rubber coupling unit 45 having the above-described configuration, it is possible to realize a steering apparatus for an automobile that achieves both reduction of flutter and improvement of steering feeling. Further, the configuration of the rubber coupling unit is not limited to the configuration shown in FIG. 8, but may be any other configuration as long as the equivalent torsion spring constant of the rubber coupling can be changed in the flutter region and the steering region. Is also good. 19 to 24 show specific examples thereof. The parts shown in each figure are parts corresponding to the small holes 48 and the centering shaft 49 shown in FIG.

In the example shown in FIGS. 19 to 21, a cylindrical inner cylinder 96 is inserted into a cylindrical outer cylinder 95, and the outer cylinder 95 and the inner cylinder 96 are swingably connected by pins 97. The configuration is as follows. As shown in FIG. 20, a cushioning member 98 (for example, made of rubber or the like) is provided on the inner wall of the outer cylinder 95 so as to face the inner cylinder 96.
A gap d is formed between the cushioning member 98 and the inner cylinder 96.

With the above configuration, as shown in FIG. 21, the outer cylinder 95 and the inner cylinder 96 can be rotationally displaced with one degree of freedom about the pin 97 as the center of rotation. The range of rotation is the range of the gap d and the amount of deformation of the cushioning material 98. However, since the amount of deformation of the cushioning member 98 is very small, the rotatable range can be approximated to the gap d.

Assuming that the distance from the position where the pin 97 is provided to the end of the outer cylinder 95 is L, the rotation angle θ between the outer cylinder 95 and the inner cylinder 96 (hereinafter referred to as a minute bending angle θ) is tan θ =
It can be approximated by the equation shown by d / L. That is, the small bending angle θ between the outer cylinder 95 and the inner cylinder 96 is
7 can be arbitrarily set by appropriately selecting the arrangement position (equivalent to the distance L).

In the above structure, when a bending moment is generated in the shaft composed of the outer cylinder 95 and the inner cylinder 96, the inner cylinder 96
Is rotationally displaced around the pin 97 as a center of rotation until a contact with the outer cylinder 95 via the buffer member 98 is made possible. After the contact, the rotation of the outer cylinder 95 and the inner cylinder 96 is restricted, and the two 95, 96 can be regarded as rigid bodies.

Therefore, in the structure shown in FIGS. 19 to 21, the area until the inner cylinder 96 comes into contact with the outer cylinder 95 becomes a flutter area, and after the inner cylinder 96 comes into contact with the outer cylinder 95, it becomes a steering area. . Further, since the above-mentioned minute bending angle θ is an angle when the inner cylinder 96 comes into contact with the outer cylinder 95, the minute bending angle θ
Will define the range of the flutter area.
Further, as described above, the small bending angle θ is determined by the gap d and the distance L.
Can be set arbitrarily by selecting. Therefore, the range of the flutter region can be arbitrarily set by appropriately selecting the gap d and the distance L.

On the other hand, in the example shown in FIGS. 22 to 24, a prismatic inner cylinder 100 is inserted into a prismatic outer cylinder 99, and the outer cylinder 99 and the inner cylinder 100 are connected to a connecting member 101 (pear cloth). (Shown in FIG. 2) so as to be able to swing. The inner wall near the end of the outer cylinder 99 has an inner cylinder 100
A cushioning material 102 (for example, made of rubber or the like) is provided so as to face the cushioning member 102 and the inner cylinder 100.
Is formed so as to form a gap between them.

That is, since the inner cylinder 100 is supported by the connecting member 101, the inner cylinder 100 is opposed to and separated from the outer cylinder 99 when no external force such as a bending moment is applied as described later. Have been. Note that FIG. 23 is a view taken along the line AA in FIG. 22, and FIG. 24 is a view taken along the line BB in FIG.

The connecting member 101 is formed of a material that functions as a spring, such as rubber, and has a structure in which the spring constant has anisotropy depending on the direction of the applied load. Specifically, the spring constant K _{X in the} axial direction indicated by the arrow X in FIG. 22 is set small, and thus the rigidity of the connecting member 101 in the X direction is small. Further, the spring constant K _Y with respect to the axial direction indicated by the arrow Y in FIG. 22
Is set large, so that the rigidity of the connecting member 101 in the Y direction is increased. Further, the rigidity against bending direction of the spring constant K _M is set to be smaller, thus connecting member 101 with respect to the bending direction indicated by the arrow M in FIG. 22 is small.

The cushioning member 102 is formed by the outer cylinder 99 and the inner cylinder 10.
This is provided to prevent collision with zero, and unlike the connecting member 101, the spring constant does not have anisotropy, and the spring constant is set small. In the above configuration, when a bending moment is generated in the shaft composed of the outer cylinder 99 and the inner cylinder 100, the inner cylinder 100 is connected to the connecting member 10
1, the connection member 101 is displaced while being flexibly deformed until the connection member 101 comes into contact with the outer cylinder 99 via the buffer member 102. Further, after the contact, the displacement of the outer cylinder 99 and the inner cylinder 100 is regulated, so that it can be regarded as a rigid body.

Therefore, in the configuration shown in FIG.
An area until 0 comes into contact with the outer cylinder 99 becomes a flutter area, and after the inner cylinder 100 comes into contact with the outer cylinder 99, it becomes a steering area. Further, in the configuration shown in FIG. 22, unlike the configurations shown in FIGS. 19 to 21, the relative displacement between the inner cylinder 100 and the outer cylinder 99 is not limited to one degree of freedom but can be freely displaced. It is possible to improve the attachment to the steering device and to prevent an excessive load from being applied to the pin 97.

Further, in the configuration shown in FIG.
To adjust the range of the region, the connecting member 101 can be adjusted in the Y direction.
Spring constant K_YOf spring for size and bending direction
Number K _MBy adjusting the size of
Similarly to the configuration shown in FIGS. 19 to 21, the gap d and the distance L
It can be set arbitrarily by appropriately selecting.
Therefore, the range of the flutter area is set with a degree of freedom.
be able to.

On the other hand, as described above, the spring constant K _X of the connecting member 101 in the axial direction indicated by the arrow _X is set to be small, so that the rigidity of the connecting member 101 in the X direction is small. Therefore, vibration transmitted from the gear box 26 or the like to the outer cylinder 99 via the output shaft 25 (vibration transmitted in the X direction in the drawing, so-called longitudinal vibration) is absorbed by the connecting member 101. For this reason, the transmission of the longitudinal vibration to the inner cylinder 100 (the intermediate shaft 24) can be prevented, so that noise (for example, shoe noise) generated indoors due to the longitudinal vibration can be prevented.

As described above, by using the structure shown in FIGS. 19 to 24 in place of the rubber coupling, it is possible to prevent the occurrence of flutter in the flutter region, and to improve the responsiveness in the steering region. A good steering feeling can be obtained. Further, since the configuration shown in FIGS. 19 to 24 has a simple configuration as compared with the rubber coupling shown in FIG. 8, it is possible to reduce the cost of the steering apparatus for an automobile and to facilitate the assembly work. .

19 to 24, the outer cylinder 9
The shapes of the 5, 99 and the inner cylinders 96, 100 are not limited to cylindrical and prismatic shapes, but may be other shapes (for example, triangular prism shapes). Further, in the example shown in FIGS. 22 to 24, the connecting member 101 is provided at the distal end of the inner cylinder 100 and the cushioning material 102 is provided at the end of the outer cylinder 99. The arrangement position of the cushioning material 102 is not limited to this.
The same effect can be obtained by a configuration in which the positions of the and the cushioning material 102 are reversed.

FIGS. 10 to 13 show a reduction in flutter with respect to the vehicle steering device 20 shown in FIG. 1 (which has the same configuration as the vehicle steering device 20D shown in FIG. 7 as described above). Shows the experimental results when an experiment was performed to verify the above. FIG. 10 shows the ratio between the steering rotation angle and the pinion rotation angle when the gear box 26 is fixed and the rack bar 36 is vibrated in the vehicle steering system 20. In the figure, the horizontal axis represents the rack bar 36.
, And the vertical axis indicates the ratio between the steering rotation angle and the pinion rotation angle. Also,
The characteristic shown by the solid line is the characteristic of the vehicle steering device 20,
The dashed lines show the characteristics of the conventional automobile steering system.

As shown in the drawing, the ratio between the steering rotation angle and the pinion rotation angle is substantially lower in the vehicle steering system 20 according to the present embodiment than in the conventional vehicle steering system. In particular, it can be seen that the flutter frequency is as low as about 6.7 dB at the flutter frequency where flutter occurs. Therefore, as shown in the figure, the vehicle steering device 20 according to the present embodiment is compared with the conventional vehicle steering device.
It can be seen that fluttering is more suppressed.

FIG. 11 shows the characteristics when the vehicle steering system 20 is actually mounted on a vehicle. Specifically, the unbalanced wheels are used to forcibly generate flutter. 20 shows the result of examining the state of flutter occurrence when the vehicle steering device 20 is mounted on a vehicle. As an experimental method, a vehicle equipped with the above-described vehicle steering device 20 was driven on a chassis roller, and flutter generated at this time was detected as steering circumferential acceleration. The figure also shows, for comparison, the characteristics of a conventional vehicle steering system (shown on the left).

As is apparent from FIG. 7, even in the actual vehicle state, the occurrence of flutter is reduced in the vehicle steering device 20 according to the present embodiment as compared with the vehicle steering device having the conventional configuration. I understand. In addition, the reduction rate is a very large reduction rate of 44%. Therefore, the experimental results shown in FIG. 11 demonstrate that the flutter can be greatly suppressed by applying the vehicle steering system 20 according to the present embodiment even in the actual vehicle state.

FIGS. 12 and 13 show the results of experiments conducted on the influence on the steering feeling. still,
FIG. 12 shows the steering feeling characteristics of the vehicle steering system 20 according to the present embodiment, and FIG. 13 shows the steering feeling characteristics of the conventional vehicle steering system. Also,
In each figure, the horizontal axis represents the steering angle MA, and the vertical axis represents the steering torque MT.

The steering feeling can be determined from the inclination of the steering torque MT with respect to the steering angle MA and the hysteresis width. Therefore, the steering feeling characteristics of the vehicle steering system 20 according to the present embodiment shown in FIG.
3, the characteristics are similar, and the inclination of the steering torque MT with respect to the steering angle MA and the hysteresis width have substantially the same value. Accordingly, it is understood that the steering apparatus 20 for a vehicle according to the present embodiment in which the rubber coupling 40 is provided can obtain a steering feeling substantially equivalent to that of the conventional vehicle steering apparatus.

From the results of the above experiments, it has been proved that the vehicle steering system 20 according to the present embodiment can reliably suppress the occurrence of flutter and maintain good steering feeling characteristics. Was. In the embodiment described above, an example is shown in which the steering shaft 22 is constituted by the three shafts of the input shaft 23, the intermediate shaft 24, and the output shaft 25 as the vehicle steering device 20, but the present invention is composed of two steering shafts. It is also possible to apply the present invention to an automobile steering system (a so-called two-link type steering system) in which the shafts are connected by one hook joint.

That is, when the steering angle of the steering when the vehicle is traveling straight is zero, one of the yokes constituting the hook joint is disposed so as to be substantially perpendicular to the plane including the two shafts. By arranging the rubber coupling (low-rigid member) on the shaft side having the yoke arranged so as to be able to cause bending deformation of the rubber coupling by the bending moment, the equivalent torsion spring constant can be reduced. Can be reduced. Thereby, the rotational vibration of the pinion can be absorbed by the rubber coupling, and fluttering of the steering can be prevented.

Next, a second embodiment of the present invention will be described. 14 and 15 show a vehicle steering system 60 according to a second embodiment of the present invention. FIG. 14 shows an enlarged view of a main part of the vehicle steering device 60, and FIG. 15 shows the entire configuration of the vehicle steering device 60. 14 and 15, the same components as those of the vehicle steering system 20 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Also in this embodiment, the steering shaft 62 is composed of three shafts: an input shaft 63, an intermediate shaft 64, and an output shaft 65. The steering shaft 21 is provided at the upper end of the input shaft 23. The lower end of the output shaft 25 is connected to a gear box 26. Also, steering 2
1 is mounted on the vehicle so that the input shaft 63 is supported by the vehicle.
, The input shaft 63 is not displaced by this vibration (however, the intermediate shaft 64 and the output shaft 65 are displaced by the translation vibration in the gear box 26).
The input shaft 63 and the intermediate shaft 64 are connected to the first hook joint 70.
, And the intermediate shaft 64 and the output shaft 65 are connected by a second hook joint 71.

The first hook joint 70 has an input shaft side yoke 67 which rotates integrally with the input shaft 63, and an intermediate shaft side yoke 68 which is formed at the upper end of the intermediate shaft 64 and rotates integrally with the intermediate shaft 64. And a cross pin 69 (configured by pins 69a and 69b) rotatably connected to the yokes 67 and 68.

Further, the second hook joint 71 is
An intermediate shaft side yoke 72 formed at the lower end of the shaft 4 and rotating integrally with the intermediate shaft 64, an output shaft side yoke 73 rotating integrally with the output shaft 65, and rotatably connected to the yokes 72 and 73. And a cross pin 74 (configured by pins 74a and 74b).

In this embodiment, when the steering angle of the vehicle when the vehicle is traveling straight is zero, the first and second hook joints 71 and 72 are connected to each other. The input shaft 63, the intermediate shaft 64, and the output shaft 65 are respectively in the same plane S2 (shown in FIG. 14).
And the input shaft side yoke 67 and the output shaft side yoke 73 are both arranged to be perpendicular to the plane S2.

By configuring the input shaft 63, the intermediate shaft 64, the output shaft 65, and the first and second hook joints 71 and 72 as described above, the first hook joint 70 is formed as shown in FIG. Cross Pin 69 and Second Hook Joint 7 Constituting
The cross pin 74 that constitutes 1 faces three-dimensionally and parallel to each other. More specifically, the pin 69a extending in the vertical direction of the cross pin 69 and the pin 74a extending in the vertical direction of the cross pin 74 are parallel to each other, and the pin 69b extending in the horizontal direction of the cross pin 69 and the cross The pins 74b extending in the lateral direction of the pins 74 are also parallel to each other. Therefore, with the above configuration, the pin 69a and the pin 74a form a four-node parallel link, and similarly, the pin 69b and the pin 74b also form a four-node parallel link.

Next, the operation of the vehicle steering system 60 in the case where forced vibration occurs in the wheels and the gear box 26 undergoes translational vibration will be described. When forced vibration is generated in the wheel and translational vibration is generated in the gear box 26, the translational vibration is generated by the shafts 63 to 65 and the first and second hook joints 7.
Acts on 0,71. However, as described above, the cross pin 69 forming the first hook joint 70 and the cross pin 74 forming the second hook joint 71 face each other in three dimensions and in parallel. Therefore, even if the output shaft 65 moves in the vertical direction, the front-rear direction, and the left-right direction (indicated by arrows in FIG. 15) in the gear box 26 due to the translational vibration, the translational vibration is converted into rotational vibration by the respective hook joints 70, 71. It is not converted.

Here, in order to clarify the above matter,
From the state shown in FIG.
FIG. 18 shows an automotive steering system 80 having a configuration rotated by degrees. In the figure, the same reference numerals are given to the components corresponding to the components shown in FIG.

As described above, each cross pin 69, 74 is
In the vehicle steering device 80 rotated by °, the pin 69b of the cross pin 69 and the pin 74b of the cross pin 74 do not become parallel due to the intersection angle φ. Therefore, when the gear box 26 is displaced in the left-right direction (indicated by an arrow H in the drawing) in the vehicle steering system 80 having this configuration, this displacement is applied to the input shaft 63 at the first and second hook joints 70 and 71. And the input shaft 63 is rotated as indicated by an arrow N in the figure. Therefore, rotational vibration is generated on the input shaft 63 by the translation vibration of the gear box 26, and the steering 21
Flutter occurs.

Therefore, the first and second hook joints 70,
In order not to convert the translational vibration of the gear box 26 into a rotational component at 71, in other words, to prevent flutter from occurring in the steering 21, the cross pin 69 constituting the first hook joint 70 and the second pin 69 Hook joint 71
Must be opposed to each other in three dimensions in parallel. Therefore, by using the configuration shown in FIG. 14 for the vehicle steering device 60, it is possible to prevent flutter from occurring.

FIG. 16 shows an arrangement in which the input shaft 63, the intermediate shaft 64, and the output shaft 65 are arranged on the same plane, and
2 shows the results obtained by simulating the flutter rotation angle sensitivity when the angles of the cross pins 69 and 74 are set to zero and the angles of the cross pins 69 and 74 are gradually changed from this state. . Here, the rotation angle sensitivity of the flutter indicates the rotation angle of the steering 21 when the gear box 26 is moved in a predetermined direction (vertical direction, front-back direction, left-right direction) by 1 mm as shown in FIG. Therefore, the larger the rotation angle sensitivity, the larger the flutter. As is clear from FIG. 16, when the angles of the cross pins 69, 74 are gradually changed, the cross pins 69, 74 are changed by 90 ° in all directions of the up-down direction, the front-rear direction, and the left-right direction. On the other hand, a point at which the flutter rotation angle sensitivity became zero occurred. In this regard, even if the gearbox 26 is displaced in any of the vertical direction, the front-rear direction, and the left-right direction, the steering 2
No rotation occurs at 1. Therefore, the flutter can be prevented from occurring by making the angles of the cross pins 69 and 74 coincide with this point.

As described above, the vehicle steering system 80 shown in FIG. 18 is different from the vehicle steering system 60 shown in FIG.
In this example, the cross pins 69 and 74 are rotated by 90 °. Therefore, even if the gear box 26 is displaced in any of the vertical direction, the front-rear direction, and the left-right direction, the steering 2
The configuration in which rotation does not occur in 1 is the vehicle steering device 60 itself shown in FIG. Therefore, the results of the simulation shown in FIG. 16 also demonstrate that the vehicle steering device 60 having the configuration shown in FIGS. 14 and 15 prevents the occurrence of flutter.

Next, a third embodiment of the present invention will be described. FIG. 17 shows a vehicle steering system 90 according to a third embodiment of the present invention. In FIG. 17, the same components as those of the vehicle steering devices 20 and 60 according to the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.

In the vehicle steering apparatus 20 according to the first embodiment, when the steering angle of the steering wheel 21 when the vehicle is traveling straight is zero, the plane S including the output shaft 25 and the intermediate shaft 24
1, the output shaft yoke 33 is arranged to be substantially vertical, and the output shaft 25 having this output shaft yoke 33
By providing a rubber coupling 40, flutter generated by rotation of the pinion 35 is prevented (see FIGS. 1 and 2).

On the other hand, in the vehicle steering apparatus 60 according to the second embodiment described above, when the steering angle of the steering when the vehicle is traveling straight is zero, the input shaft 63, the intermediate shaft 64, and the output shaft 65.
Are arranged in the same plane S2, and the input shaft side yoke 67 and the output shaft side yoke 73 are both arranged so as to be perpendicular to the plane S2, thereby preventing flutter caused by translational vibration of the gear box 26. (See FIGS. 14 and 15).

The steering apparatus 90 for a vehicle according to this embodiment is
The vehicle steering device 20 according to the first embodiment and the vehicle steering device 60 according to the second embodiment have a configuration in which the vehicle steering device 20 is fused. Specifically, the input shaft 63, the intermediate shaft 64, and the output shaft 65 are provided.
Are arranged in the same plane S3, the input shaft side yoke 67 and the output shaft side yoke 73 are both arranged perpendicular to the plane S3, and the rubber coupling 40 is attached to the output shaft 65 where a bending moment is generated. The configuration was provided.

With the above configuration of the vehicle steering system 90, both the effects of the vehicle steering system 20 according to the first embodiment and the effects of the vehicle steering system 60 according to the second embodiment can be enjoyed. Therefore, it is possible to prevent both the flutter generated by the rotation of the pinion 35 and the flutter generated by the translational vibration of the gear box 26.

The application of the present invention is not limited to the above-described hook joint using a cross pin, but can also be applied to a universal joint having another structure. FIG. 27 shows a universal joint 110 having another configuration to which the present invention can be applied. The universal joint 110 shown in FIG.
1 is connected to a first connecting member 113 via a vertical axis 115, and the first connecting member 113 is configured to be rotatable about the vertical axis 115.

The output shaft 112 is connected to a second connecting member 114 via a first horizontal shaft 116, and the second connecting member 114 is rotatable about the first horizontal shaft 116. It has a configuration. Further, the first connecting member 113 and the second connecting member 114 are connected by a second horizontal shaft 117, and each of the connecting members 113 and 114 is connected to the second horizontal shaft 1
17 is rotatable.

In the universal joint 110 having the above-described structure, the intermediate shaft 111 and the output shaft 112 when the vehicle travels straight ahead.
11 constituting the universal joint 110 with respect to a plane including
6, 117 can be arranged so as to be substantially vertical. Therefore, by disposing the low-rigidity member on the shaft having the shafts 116, 117 arranged so as to be vertical, the occurrence of flutter can be suppressed. it can.

Further, the configurations of the vehicle steering devices 20, 60, and 90 according to the embodiments described above can be applied to devices that transmit torque using a hook joint other than the vehicle steering device. In this case, it is possible to suppress vibration accompanying torque transmission.

[0100]

According to the present invention as described above, the following various effects can be realized. According to the first aspect of the invention, when rotational vibration occurs in the pinion due to forced vibration of the wheel, the rotational vibration is disposed on the shaft where the bending moment is generated, thereby reducing the equivalent torsion spring constant. Absorbed by low rigidity members. Therefore, since the rotational vibration of the pinion is blocked by the low-rigidity member, it is possible to prevent flutter from occurring in the steering.

According to the second aspect of the present invention, even if translational vibration occurs in the gear box, each hook joint does not convert the translational vibration into rotational vibration, so that the translational vibration is cut off at each hook joint. The occurrence of flutter can be prevented. Further, according to the third aspect of the invention, both the effects of the first aspect of the invention and the effects of the second aspect of the invention can be enjoyed. Therefore, the flutter and the gear generated by the rotational vibration of the pinion can be obtained. Flutter generated by translational vibration of the box can be prevented together.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle steering system according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the vehicle steering system according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining the behavior of the rubber coupling, the intermediate shaft, and the output shaft when a bending moment generated on the output shaft is applied.

FIG. 4 is a configuration diagram showing an automobile steering device in which the arrangement position of a rubber coupling is variously changed.

FIG. 5 is a configuration diagram showing an automobile steering system in which the arrangement position of a rubber coupling is variously changed.

FIG. 6 is a configuration diagram showing an automobile steering device in which the arrangement position of a rubber coupling is variously changed.

FIG. 7 is a configuration diagram showing an automobile steering system in which the arrangement position of a rubber coupling is variously changed.

FIG. 8 is a diagram showing a rubber coupling unit capable of obtaining good torsion spring characteristics in both the flutter region and the steering region.

FIG. 9 is a diagram showing characteristics of the rubber coupling unit shown in FIG.

FIG. 10 is a diagram showing a change in a ratio between a steering rotation angle and a pinion rotation angle when a gear box is fixed and a rack bar is vibrated in an automobile steering system.

FIG. 11 is a diagram showing experimental results obtained by examining the state of flutter generation in a case where an unbalanced wheel is attached to a vehicle steering system in order to generate flutter and the vehicle steering system is actually mounted on a vehicle. It is.

FIG. 12 is a diagram showing an experimental result obtained by investigating an influence on a steering feeling of the vehicle steering system according to the present invention.

FIG. 13 is a diagram showing an experimental result obtained by examining an influence on a steering feeling of a conventional automobile steering device.

FIG. 14 is an enlarged view of a main part of a vehicle steering system according to a second embodiment of the present invention.

FIG. 15 is an overall configuration diagram of a vehicle steering system according to a second embodiment of the present invention.

FIG. 16 is a diagram showing a result of simulating the rotational angle sensitivity of flutter when the rotational angle of the cross pin is changed.

FIG. 17 is an overall configuration diagram of a vehicle steering system according to a third embodiment of the present invention.

18 is a configuration diagram showing a vehicle steering system having a configuration in which each cross pin is rotated by 90 degrees from the state shown in FIG. 14;

FIG. 19 is a view showing a joint structure in which an outer cylinder and an inner cylinder are connected using pins.

20 is a cross-sectional view of the configuration shown in FIG.

21 is a diagram for explaining the operation of the configuration shown in FIG.

FIG. 22 is a diagram showing a joint structure in which an outer cylinder and an inner cylinder are connected using a connection member having spring properties.

FIG. 23 is a view as seen from the direction of arrows AA in FIG. 22;

24 is a view as viewed in the direction of arrows BB in FIG. 22.

FIG. 25 is a diagram for explaining flutter generated by rotation of a pinion.

FIG. 26 is a diagram for explaining flutter generated by translational vibration of the gear box.

FIG. 27 is a view showing a universal joint having another configuration to which the present invention can be applied.

[Explanation of symbols]

 20, 60, 90 Automotive steering system 23, 63 Input shaft 24, 64 Intermediate shaft 25, 65 Output shaft 26 Gear box 27, 67 Input shaft side yoke 28, 32, 68, 72 Middle shaft side yoke 29, 34, 69 , 74 Cross pin 30, 70 First hook joint 31, 71 Second hook joint 33, 73 Output shaft side yoke 35 Pinion 36 Rack bar 38 Rack 40 Rubber coupling 45 Rubber coupling unit 46 Flange 48 Small hole 49 Centering Shaft 95, 99 Outer tube 96, 100 Inner tube 97 Pin 98, 102 Shock absorber 101 Connecting member 110 Universal joint

Claims (3)

(57) [Claims] At least two shafts including at least an input shaft connected to a steering wheel and an output shaft connected to a gear box, and a pair of connected shafts connected by a universal joint. In the vehicle steering system, when the vehicle is going straight, one of the yokes constituting the universal joint is arranged to be substantially perpendicular to a plane including the pair of shafts, and the yoke is arranged to be substantially perpendicular to the plane. A steering device for an automobile, wherein a low-rigidity member for lowering the rigidity of the shaft in the bending direction is disposed on the shaft side having the following. 2. An input shaft connected to a steering wheel is connected to a first shaft.
A steering apparatus for an automobile having a configuration in which the intermediate shaft is connected to an output shaft connected to a gear box via a second universal joint while the vehicle is traveling straight. The input shaft, the intermediate shaft, and the output shaft connected by the first universal joint and the second universal joint are respectively arranged on the same plane, and the yokes on the input shaft side and the output shaft side are positioned with respect to the plane. A steering device for a vehicle, wherein the steering device is arranged to be substantially vertical. 3. The steering apparatus according to claim 2, wherein at least one of the input shaft and the output shaft is bent.
A steering apparatus for an automobile, wherein a low-rigidity member for reducing directional rigidity is provided .